To start off this section of the blog dedicated to my 2007 E90 335i I figured I would start with an introductory post to my car and myself. Without further ado I will dive into the introduction.


My name is Zach, and along with my brother and business partner Jake, we run this awesome BMW N54 community. As college students, we were passionate about business as well as cars and saw an opportunity to help fellow DIY’ers get access to high-quality OEM parts at wholesale pricing. The decision to supply the BMW market was an easy decision that was fueled by our obsession with the N54, 3.0L TT engine.

A few years prior to starting BMW N54 Tuners I drove a 2008 535i and immediately joined the online BMW community. Over the following years, my brother and I saw the development of the n54 and began to learn more about its immense potential as a tuners car. Finally, in May of 2014 I came across the opportunity to acquire a 2007 E90 335i with 76,000 miles. This 335i was equipped with the sport package and factory oil cooler. I had been waiting on finding the right deal on a 335i for months and did not hesitate to jump on the opportunity.

My First Mods

I was so excited to finally have the E90 335i I had been waiting for. The car ran great as I bought it and didn’t show any signs or symptoms of misfires or any other issues so I dove straight into mods. I knew the JB4 and DCI’s (Dual Cone Intakes) had to be my first modifications. Within a few weeks of purchasing the car I had ordered and installed the JB4 G5 and DCI. After installation I briefly played around with the JB4 settings and headed out for a drive to let oil temperatures warm up to 160.

My adrenaline was pumping and it felt like it took hours to warm up with the anticipation of my first WOT acceleration with the mods. Finally! Oil temperatures were at 160 and I was ready to go. As I laid into the throttle I was impressed at how the JB4 seemed to eliminate some turbo lag (not that it is very noticeable stock), however, boost was peaking at barely over 10psi and oscillated a lot. I knew something was wrong. I spent the next week or so narrowing down the issues and finally replacing the spark plugs and ignition coils.

I realize that was a long story for an issue as simple as old spark plugs and ignition coils, but DO NOT make the same mistake as me. If you buy an n54 with the plans to modify it in the near future save yourself the trouble and buy spark plugs and coils immediately. The n54 is well known to suck the life out of plugs and coils so they really are the best, first “mod” to install on the car. I say this because the difference in power and response is immense with the new parts.


The Trouble Doesn’t Stop There

Once I replaced the spark plugs and ignition coils the car immediately developed a very rough idle. I quickly found out that the car also had faulty fuel injectors that were leaking and causing more issues with misfiring. Many early model N54’s are covered under a fuel injector recall, however, mine did not fall in this category. After a month of haggling BMW to replace these under the recall I decided to give up and replace these on my own. Finally! The car was running just as it should; no more misfires or rough idle.


The Mod Bug

With Map 5 engaged I went out for a drive and was able to get my first “real” pulls with the car running perfectly. And holy s*%^ was it fast. I got my first experience of the mod bug. I immediately drove to the nearest E85 station and filled up with a 25% mixture of e85. To date, this has been my favorite “mod” for the n54. The performance increase was amazing and the engine began running much smoother. Maybe this was all out of my excitement, and still is, but the engine seems to make a deeper and smoother sound with the E85. A few months later I decided to order the VRSF catless downpipes, which were a PITA to install. It’s possible my lack of a garage and doing this install with about 8” of snow on the ground influenced this experience. Damn Colorado! Again, my butt-dyno definitely approved of this mod. The turbos spooled much quicker at lower RPM’s and delivered torque quicker with more intensiveness. The now lack of traction even with Michelin PSS tires confirmed this.

In early 2016 I began to gain interest in MHD flash tunes and coupling that with the JB4. However, running snow tires here in Colorado made traction hard to come by during winter months. Perfect! This gave me time to take care of the waste-gate rattle that I was experiencing. The original turbos ran very strong even at 81,500 miles, but thanks to BMW’s 8 year, 82,000 mile extended warranty on the turbos, I decided to give it a shot.


New OEM Turbos

Despite my modifications and the BMW dealership knowing of these mods they agreed to replace the original turbos under the extended warranty (I got set up with an excellent service advisor). I got the car back with the new turbos and they ran slightly stronger, but the difference was less noticeable than any of the mods I had done to date. I drove the car around for about 400 miles on the stock tune to give the turbos a little bit of time break in despite the fact that this isn’t necessary. Still having the snow tires on the car I decided to drive around with only the JB4, DCI, and DP’s for another 600 miles.

May didn’t come around quickly enough, but when it finally did, it was time to swap back to the Michelin PSS and give the MHD E85 flash tune a run for its money. I flashed my ECU with the MHD tune using the JB4 handcuffed to it and filled up with 35% E85 (just under the max amount the stock LPFP can flow). I hooked up my tablet to the JB4 BT cable and prepared to log my first runs with the MHD flash tune. I eased onto the throttle at 40MPH in 2nd gear and I don’t even know how to describe the sensation. The turbos immediately spooled to 18.5psi and the car started to slide as the Michelin PSS struggled to hook up. As I shifted into 3rd at 60mph the tires spun briefly as the turbos managed to boost to a staggering 20psi. I was speechless. The 335i was running faster and smoother than ever; the data logs looked flawless. No misfires, the timing was great and consistent across all cylinders, the LPFP was nearly out of room but did its job. Despite the great news this was very short lived.


Blown Bank 2 Turbo

About 500 miles after switching to the MHD Flash tune the turbos began to sound unhealthy and were spooling very, very slowly. I drove to the dealership and mentioned the issues; they quickly looked into the issue and determined nothing was wrong. The next day as I was driving down the freeway I got on the gas a bit to pass someone; I heard a very faint popping sound and noticed smoke was pouring out of the exhaust. I went back to the dealership and they willingly replaced the faulty bank 2 turbo under warranty. Another 300 miles went by on the new turbo when suddenly the brand new bank 2 turbo blew again. Once again, they very willingly replaced the bank 2 turbo after one of BMW’s head mechanics came to look at my car.

I will write another blog post in the future to discuss the issue with the blown bank 2 turbo as I learned some valuable information after a lengthy discussion with BMW’s “head mechanic”. To give a short explanation to this, he believed the issue could be attributed to a leaking PCV (positive crankcase ventilation) valve. The PCV valve vents from the bank 2 turbo, which was likely causing the bank 2 turbo to over work as it was trying to create additional pressure that was leaked out due to the faulty valve.


Future Plans

After the issues with blowing my bank #2 turbo I decided to ditch the MHD flash tune and go back to running the JB4, DCI, DP’s and a 25% E85 mixture. As I daily drive my 335i the power from those mods alone is plenty for most situations. However, the mod bug still lives within me and I have many more plans for the future (I will likely commit to doing all of the mods at roughly the same time).

As my brother has goals for his 600hp build it is my goal to ensure I am making more power than him. With that being said, here is a brief list of the future mods I am looking into:

-Super RB Evo 19T

-Port Injection and 100% e85

-Walbro LPFP


-Manual Transmission Swap (I’m not sure the Level 10 trans will hold the kind of power I am looking to make in the long run).

Obviously, this is a short list of the mods as there are many more supporting mods that I will need in order to achieve my goals. This section of the blog will be dedicated towards my experiences with my 335i as well as progress towards reaching my build goals.

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